Rob Hoos' Tipping and its Avoidance: a Style Guide for Coffee Roasters (PDF)

February 1st, 2023, 2:31 pm

$5 for 8000 words. I just bought the PDF and had a quick scan. I can't really summarize without giving away the whole paper, but if you liked Hoos' Modulating ... publication then this is in a similar prescriptive style, but on one topic. In terms of prescriptions, probably most applicable to conventional-airflow commercial drum roasters because the prescriptions involve measuring and controlling intake air temperature and airflow, although there are a very few words about the Bullet.

Sample pages at: https://hoos.coffee/shop/p/tipping-and- ... ntent=name

#2: Post by **mpdeem** » February 1st, 2023, 5:42 pm

Thanks for sharing - quite a bargain indeed. Just got a copy.

I have Rob's Modulating the Flavor Profile of Coffee - great resource even for a humble popper roasted like me. I would highly recommend it to anyone irregardless of roast platform, as the basic logic of his methodology seems fairly universal. The most difficult aspect for me was the terminology - but I learned to roast way back when home roasters had not yet codified such nifty terms as ROR nor had access to such wonderful roast profiling programs. As I said..it was a long time ago....dinasours were still around when I learned to roast

Tipping - I find that if my charge temp is too hot, I end up with a lot more tipping. Given that I am on a popper, I basically don't charge unless the ambient temp is abnormally cold - like below 65F. In the past I tried charging at different temps ranging from 200-300 F but ended up with roasts that seemed to lack acidity plus more tipping. I alsonoticed that my ROR was too quick with higher charging temps.

After reading Rob's comments about charge temp being tied to batch size, I realized that for my small roasts, ambient temps (usually 73-78F) were adquate. Having said that, I would love to hear from any popper roasters who do charge their poppers. In any case I rarely get tipping now unless I cram too many beans in my little roast chamber.

#3: Post by **yakster** » February 1st, 2023, 11:24 pm

Thanks for the review, I've been meaning to pick this up. I roast 600 gram batches in the Bullet so charge temps are very much a thing for me.

February 1st, 2023, 11:55 pm

I should clarify that when I wrote "there are a very few words about the Bullet," the words are in the vein of: This is what happened on the USRC 3kg, but that behaviour didn't happen on the Bullet, and maybe this is why ...

If I had a Bullet, then I'd say the "very few words" would be worth $5 to me.

#5: Post by **yakster** » February 1st, 2023, 11:59 pm

I actually haven't had many issues with tipping on the Bullet, but I'm still interested.

#6: Post by **Chert** » February 2nd, 2023, 12:02 am

Is it clear where the intake airflow temperature is best measured?

February 2nd, 2023, 1:25 am

I think that the location depends on the airflow path of the roaster.

For example, on my traditional cast-iron solid-drum roaster, I put the probe at the back just behind the drum at the same height as the top of the airholes drilled in the back of the drum, and, fortunately for me, Hoos is in agreement for that style of roaster (although he uses different criteria). It has been a few years since I put the intake air temperature probe in so I can't remember where I heard that is where the intake air probe should go in an old Probat, but that is what I went by. However, other roaster designs have different airflow paths and so the location may well be different. The booklet has a short appendix that contrasts traditional-type roaster airflow vs. Giesen vs. sample (barrel) roasters vs. Bullet.

#8: Post by **Chert** » February 2nd, 2023, 9:49 am

The Huky has perforated back plate So probably at the 12 o'clock one inch below the top of drum would be as good as any for 'inlet' probe location

February 2nd, 2023, 11:28 am

Sounds reasonable. Mind you, if you have the perforated drum installed then that would probably change airflow.

Now that I've slept on it, I do recall that I had to fiddle around a bit to locate the probe close enough to the drum yet far enough away so that the probe didn't hit the drum when the roaster was hot. That may have had something to do with the mount I had to make for the thermocouple, though. (The back of the roaster is cast-iron and I didn't want to drill cast iron, and so I made a bracket out of Aluminium bar stock.)

ETA, see Aluminium flat bar bracket right rear (ignore green arrow):

#10: Post by **Milligan** » February 2nd, 2023, 6:27 pm

Cool booklet! I really enjoyed his discussion on inlet temp vs exhaust temp relating to air flow. I have an inlet probe on my USRC but I need to add one to my Cormorant. Not looking forward to drilling stainless steel... I think this may be the key to why I get some funky ET vs BT behavior. IT is probably my missing link. Definitely worth the $5 a few times over.